Uses M3 screws and either nuts or the holes are sized for 4mm x 3mm heatset inserts.
If you are left handed, would be best to mirror it which supports the blade better.
The author remixed this model.
Changed from using box cutter blade to razor blades. Mirrored for right handed user as the blades are flimsy so is supported better when pulling on the wire. If you are left handed, would be best to mirror it the other way.